Jet-type drilling jar



March 23, 1954 w. s. CRAKE JET-TYPE DRILLING JAR Original Filed Dec. 28,1948 INVEHTOIZ'.

WILF'RED S. CRAKE Hl5 ATTORNEY Patented Mar. 23, 1954 UNITED STATES TENTOF FlCEi Development.

Company, San Francisco,

Califi,

acorporation of Delaware;

Original. application December 28, 1948, Serial No. 67.708. Divided andthis application November 18, 1952, Serial No. 321,136

2 Claims.

This application 1 is a division 1 of my copending application SerialNumber 67,708, filed on: the

28th day of December; 2635.853.

1948 now U. S; PatentflNo.

This: invention relates to a well tool and per tains more particularlyto a jarring tool which may belowered on a cable through a drill stringfor applyingajarring forceto said drill string.

In drilling an oil well, it occasionally happens thattthe tubing ordrill string becomes jammed in: the well: borehole by cavings of sand,formation debris or rock fragments falling into. the boreholeand'wedgingthe drill string and drill bit' attached thereto. The.wedging materials aroundthe bit or drill'string are frequently compactedto such extent that circulation of drilling fiuidcannot be relied upon.to wash them away and release the bit. Accordingly, the bit or drillstring can only be freed by applying a severe jarring action tothe stuckmember.

A tool commonly used. is a mechanical jar adapted to be attached to thelower end of a drill string and. run into the well, where it isconnectedto that portion of the drillstring that islodgedl in the jarpermits a reciprocating or limited vertical movement of the upper partof the drill string, said reciprocating movement causing jarring actionto. the stuck' portion of the drill string. The-main disadvantage withthis type of jar is that the drill string must be withdrawn fromthewell, equipped: with the jar, and then reinserted into thewell to beconnectedito the stuck section of drill: string in the well.

The primary objectof the present invention is to provide a jarring tooladapted to be lowered on a cablewithin a drill string and positioned in'a stuck section of said drill string for engagement therewith;

Another object of this invention is to provide a cable jarring tooladapted to effect a jarring and strong uplifting action at the point, orclose to the point, at which the drill string is stuck or wedged.

A further object of this invention is to provide a cable jarring tooladapted to impart a jetting effect to a well fluid within the drillstring to aid or restorecirculation within thewell whereby said fluidmay dislodge and wash away any materials that tend to immobilize thedrill string.

Another object of this invention is to provide a jarring tool of simpleand sturdy construction that is readily insertable into and removablefrom a drill string without the removal of any portion of said drillstring.

well borehole. The mechanical between the outer wall Other objects andadvantages of the present.

invention will become apparent from the follow.-

ing description, taken with reference to thedraw ing, wherein:

Figure l is a longitudinalview, partly inlcross tool positioned section,of the present jarring within a rotary drill string.

Figure 2 is another jarring tool of Figure 1; after carried by said toolhas been detonated.

Figure 3 is a cross-sectional'view of the present. jarring toolincorporating a gas expansible an.

choring means.

i5, carried at the lower end of the drill string; against the wall ormore apertures H5 in outlet means: whereby, a. drilling fluid may becirculated during drilling operations by pumping it down through'thedrill string l4; out the: apertures l6 and upwards of' said. drillstring and the wall 19. ot the borehole.

The present jar lolmay be run into the well onpreferably containing an;insulated a. cable. ll, electrical conductor 38 for firing anexplosive.- It is tobe understood that an ordinary cable or wire linemay be used employed to ignite the explosive. In this. embodiment thecable II is. attached to a cable socket 39. and the electrical conductor38 is run through or alongside a sinker bar 12 and a hammer-and-anviltype mechanical jar that may be interposed between the cable H and thetool l0 toaid in sinking the tool jarring it free from the or collar M.The electrical conductor 38 conlll in the well and in tinues downwardthrough the tool 10 terminating at a chamber 33- adapted to contain adetonating mechanism. The jet-type jar I 0 comprises a cylindrical bodymember 21, reduced diameter. Carried on or formed with said body me'mber2| is a or multiple slip bowls- 23 having outer tapered faces. movementon said body 2| is a jar integrally anchoring means which comprises aring or sleeve 24 to which is attached, in any suitable manner, e. g.,welding a plurality of vertically depending slip arms 25 which may beeither hinged or made of flexible material whereby they may be spread"view in cross sectiontof the. an explosive charge l9 of: the wellborehole. One

the drill bit form fluid;

in the annular space l8;

if mechanical devices are.

surrounding drill stringa portion 22* thereof having a slip bowlSlidably mounted for limited longitudinal waterproof material orcontainer may be employed, said material or outwardly toward the innerwall of said drill string M. The lower ends of the slip arms 25 areprovided with gripping elements or slips 2% having toothed or serratedfaces that are curved to conform to the inner surface of the drillstring M. The slips 25 are mounted in slidable engagement with the slipbowls 23, being normally held in their retracted position, as shown inFigure 1, by a tension spring 21. Pins 28 or other suitable fasteningmeans secure the top of the spring 21 to the body member 2|.

Removably affixed to the bottom of the body member 2|, in any suitablemanner, as by screw threads 31, is a thick-walled cylinder 29 having acentral chamber 33 formed therein, which,

chamber contains suitable firing mechanism for igniting an explosivecharge. A thick-walled housing 30, having an axial bore 3| therethrough.is secured by screw threads 32 to the lower end of cylinder 29. Theaxial bore 3| of said housing 30 forms a chamber in which a charge ofexplosive 34 may be carried. Chamber 33 containing an explosive cap or afiring mechanism (not shown) and chamber 3| housing the explosive charge34 are interconnected by a suitable passageway 35. The lower end of theaxial bore 3| may be tapered as at 36, if desired, to concentrate andfocus the blast from the charge 34 when said charge is detonated.

Any suitable amount and type of explosive charge 34 may be useddepending on the amount of jarring and lifting action desired. Prefer-'a slow-burning type smokeless powder of the type used as a propellentcharge for military purposes. It is desirable to use a waterproof typeexplosive as the borehole of the well is generally filled with fiuid.Alternatively, an explosive charge covered with a carried in awaterproof ably the explosive is container being of an easilydestructible and relatively thin material such as, for example, rubber,plastic, parchment, aluminum or other metallic foil, and the like.

When the present jarring jar free a drill string at which the drillstring is struck is previously tool is employed to determined bysuitable means well known to the" art, such as a magnetic tester. Thejarring tool I is then attached to the end of the cable [I and loweredthrough the drill string M to the level at which the drill pipe isstuck. In this case. the cavings 28 are illustrated as wedging the drillbit |5 in place against the wall of the well Is. Hence, the jarring toolI0 is lowered to a position just above the drill bit l5. In operation,the electrical conductor cable H may be attached to a suitable powersource and switch means (not shown) at the surface. With the explosivecarrying jarring tool Ill in place as shown in Figure l, the firingmechanism or cap contained in chamber 33 is actuated or fired toigniting the explosive jet charge 34. The gases-generated by theigniting charge 34 discharge downwardly through the axial bore causingthe parts of the tool body 2|, 22, 20 and 3D to move vertically upward.

The inertia of the spring-supported slip assembly, comprising ring 24,arms 25 and slips 25.

causes it to stand momentarily substantially still whereby the spring 21is extended and the slips 26 are caused to move outwardly as the backsof the slips slide over the faces of the rising slip bowls 23. The slipsmove outwardly until the teeth of the slips 2B engage the inside of l4with drill bit I5, the point.

the drill string M, as shown in Figure 2. Thus, the upward verticalmovement of the tool body 2|, 22, 29 and 3D is arrested and theremainder of the explosive thrust is transferred to the drill string |4whereby said drill string is subjected to a sharp jarring and upliftingaction. Prior to firing the explosive 34, the drill string is preferablysubjected to a strong upward pull from the surface so that considerabletension exists in the drill string. The vertically-directed explosivereaction of the jet adds greatly and suddenly to this tension, helpingto jar the stuck drill pipe free and causing the cavings 20 to becrushed or jammed into the borehole wall l9.

After the explosive force is spent, the weight of the tool body 2 22, 29and 30 is normally sufficient to disengage the slips 26 from the innersurface of the drill string M as the drilling jar is allowed to dropslightly. If this fails to disengage the slips 26, a mechanical jar |3may be actuated by pull or release of the cable I Either action causesthe slip bowl 23 to slide down-, wardly from the position shown inFigure 2 to that shown in Figure 1, whereby the slips 26 are disengaged.The spring 21 pulls the ring 24 and attached slip arms 25 and slips 26into their retracted position (Figure 1) thus allowing the,

jarring tool It to be withdrawn to the surface by the cable Anadditional advantage of the present jarring tool is that the explosivedischarge jettingaction may be utilized to restore circulation in a wellborehole. It occasionally happens that circulation of drilling fluiddown the pipe string I it, out the apertures l6 of the bit l5 and intothe annulus I8, is blocked by cavings 2|] in the annulus l8 above thedrill bit. At such times. the pressure capacity of the mud pumps at thesurface is usually not sufficient to cause the pumped fluid to washthese cavings 20 away and restore circulation. By using the present jetjarring tool and firing it immediately above the drill bit |5, a veryhigh pressure is created inside the lower end of the drill string Mwhich is suflicient to dislodge the cavings 20 and restore.

a body member 59 having a recessed wall por-' tion 5| adapted to house aplurality of anchoring slips 52. A plurality of lateral piston chambers53 are formed in said recessed wall portion,

said chambers being in communication with an axial bore 54 in said bodymember 5|) which also serves as a chamber for housing detonating meansor materials.

'Slidingly mounted for lateral movement in; the piston chambers 53 in asubstantially fluid-- tight manner are a plurality of pistons 55 thatare fixedly secured to theinner surfaces of the anchoring slips 52.

serrated or toothed for gripping the inner surface of the drill string56 when expanded thereand into the chamber 54 housing the ignition means(not shown) Threadedly secured to the lower end of the;

Afiixed to a sinker bar l2 The slips 52 are curved to conform with theinner surface of a surround-. ing drill string 56. The faces of theslips 52 arebody member 50 is a housing member having an axial boretherethrough. The upper part 58 of the bore is enlarged to form achamber for containing an explosive charge 59 while the lower portion 60of said bore is shaped to direct the explosive blast downwardly.

In operation, the present jarring tool is lowered into a drill string 56to a predetermined depth where the charge 59 is exploded in a mannerpreviously described. A portion of the gases generated during theexplosion is forced into the axial bore 54 of the body member 50. Thepistons 55, in communication with said axial bore 54, areinstantaneously forced outwardly by the gaseous pressure causing theattached slips 52 to contact the inner wall of the drill string 56, thusfixedly anchoring the tool in place during the time period required bythe explosive bases to escape through the bore 60. It will thus be seenthat upon the firing of the explosive charge the drill string 56 issubiected to a sharp jarring and strong uplifting action in a mannersimilar to that described with regard to the apparatus of Figures 1 and2.

I claim as my invention:

1. A jarring tool adapted to be lowered on a cable within a tubularstring in a well, said tool comprising an elongated body member, achamber in said body containing an explosive charge, means incommunication with said chamber for exploding said charge, a downwardlyextending passageway from said chamber to guide the explcsive gasesescaping therefrom, whereby an upward reaction thrust is developed tomove said body member upwards, and anchoring means outwardly carried bysaid body member, radially expansible slips carried by said anchoringmeans,

a portion of the inner surfaces of said slips being in communicationwith said chamber and being actuated by a portion of escaping explosivegases to grip the inner walls of said tubular string, thereby impartingto said string a jarring upward thrust.

2. A jarring tool adapted to be lowered on a cable within a tubularstring in a well, said tool comprising an elongated body member havingan axial bore formed in the lower portion thereof and a plurality oflateral openings between said axial bore and the outside of said bodymember, a chamber forming part of the axial bore in said body containingan explosive charge, means in communication with said chamber forexploding said charge, a downwardly extending passageway frcm saidchamber to guide the explosive gases escaping therefrom, whereby anupward reaction thrust is developed to move said body member upwards,and anchoring means outwardly carried by said body member, said an- 7choring means comprising a plurality of piston means mounted in asubstantially flui'dtight manner for limited lateral movement in saidlateral openings, and gripping means ailixed to said piston means andmovable therewith, said anchoring means being actuated by a portion ofescaping explosive gases to grip the inner walls of said tubular string,whereby said upward thrust is transmitted to said tubular string.

WILFRED S. CRAKE.

References Cited in the file of this patent UNITED STATES PATENTS Number

